Multi-threat detection system

ABSTRACT

A method and system for efficiently screening for threatening items are presented. The system includes a test unit configured to subject the object to a combination of two or more different types of tests, sensors configured to receive test outcome from the object and generate corresponding output signals, and a computation unit receiving and processing the output signals to generate parameter values. The computation unit combines the parameter values from the different types of tests to determine a set of risk factors that indicate a likelihood that the threatening item is present in the object, wherein the parameter values include visualization data obtained from different measurement angles.

RELATED APPLICATION(S)

This application claims priority from U.S. patent application Ser. No.12/025,688 filed on Feb. 4, 2008 and U.S. patent application Ser. No.12/025,691 filed on Feb. 4, 2008, both of which claim priority to U.S.patent application Ser. No. 11/223,494 filed on Sep. 9, 2005 (now issuedas U.S. Pat. No. 7,337,686), which in turn claims priority from U.S.Provisional Application No. 60/608,689 filed on Sep. 10, 2004 and U.S.Provisional Application No. 60/680,313 filed on May 13, 2005.

FIELD OF INVENTION

This invention relates generally to a system for detecting the presenceof a threatening item, and more particularly to a system for detectingthe presence of a threatening item using a plurality of tests inparallel.

BACKGROUND

Today, checkpoint security systems in public places like airports orgovernment buildings typically include some combination of an imagingtest, a metal detector, and a chemical test. The chemical test usuallyuses the table-top explosive trace detection (ETD) machine in which aswab or an air sample is taken from an object (e.g., a bag) and testedfor trace explosive materials.

Unfortunately, the security check systems that are currently in use arenot as reliable as they could be. For example, the X-ray tests identifythreatening items based on object densities, and many innocuous objectshave densities that are similar to those of some threatening items.Naturally, the rate of false-negative is high. With the imaging testinvolving X-ray or CT-scan, the accuracy of the test depends largely onthe alertness and judgment of a human operator who reviews the images asthe bags are scanned. While several systems include automatic visualclassification of suspect items, reliance on human alertness andjudgment still plays a major role in these systems. Due to distractions,fatigue, and natural limitation on human attention span, a check systemthat relies so heavily on human judgment cannot reach an optimal levelof accuracy. Moreover, because imaging test relies heavily on thevisualization of objects being tested, a passenger can disguise or hidea harmful threatening item and avoid detection by the imaging test.

Attempts have been made to increase the accuracy of a checkpointsecurity system by using a combination of tests, such as imaging, metaldetector, and a chemical test. Typically, the tests are performed byutilizing three separate equipments and placing them next to oneanother. Objects are tested by the separate equipments separately andsequentially, one test after another. For example, an airport securitysystem may employ an X-ray image test and subject only bags that areindicated as being suspect by the X-ray image test to a chemical test.Similarly, as for passengers, they may first be asked to pass through apreliminary metal detection portal, and be subjected to a more stringentmetal detector test performed by a human operator only if an alarm israised by the preliminary portal test.

A problem with this type of serial/sequential combination of tests isthat the overall accuracy depends heavily on the accuracy of eachindividual test, and in some cases on the accuracy of the first test.For example, if the chemical test is not used unless a bag fails theX-ray imaging test, the use of the chemical test is only helpful if theX-ray imaging test accurately identifies the suspect bags. If theoperator reviewing the X-ray images misses a potential threatening item,the fact that the chemical test is readily available does not change thefact that the potential threatening item passed through the securitysystem.

While using multiple tests on every passenger and luggage would be anobvious way to enhance the accuracy of security checks, such solution isnot practical because it would result in passengers spending aninordinate amount of time going through the security checks. Moreover,such system would be prohibitively costly. For a practicalimplementation, the accuracy of the security check tests is balancedby—and compromised by—the need to move the passengers through the systemat a reasonable rate. Also, if a test that yields a high rate offalse-positives like the X-ray test is used as the first test, the flowof passengers is unnecessarily slowed down because many bags that do notcontain a threatening item would have to be subjected to the secondtest.

A system and method for moving the passengers through a securitycheckpoint at a reasonable rate without compromising the accuracy of thesecurity check tests is desired.

SUMMARY

In one aspect, the invention is a system for screening an object for athreatening item. The system includes a test unit configured to subjectthe object to a combination of two or more different types of tests,sensors configured to receive test outcome from the object and generatecorresponding output signals, and a computation unit receiving andprocessing the output signals to generate parameter values. Thecomputation unit combines the parameter values from the different typesof tests to determine a set of a risk factors indicating a likelihoodthat the threatening item is present in the object. The parameter valuesinclude visualization data obtained from different measurement angles.

In another aspect, the system includes a method of screening an objectfor a threatening item. The method includes subjecting the object to acombination of different types of tests for identifying properties ofthe object, reading output signals from sensors positioned to receivetest outcome from the object, processing the output signals individuallyto generate parameter values, and combining the parameter values fromthe different types of tests and using visualization data obtained fromdifferent measurement angles to determine a risk factor that indicates alikelihood that the threatening item is present in the object.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the main components of amulti-threat detection system in accordance with the invention.

FIG. 2 is a block diagram of an exemplary embodiment of the multi-threatdetection system.

FIG. 3 is a block diagram illustrating the modules of the computationunit for executing a threatening item identification method.

FIG. 4 is an exemplary embodiment of the multi-threat detection systemincluding a single test unit and multiple object units.

FIG. 5 is a block diagram showing the test unit and the object units.

FIG. 6 is another exemplary embodiment of the multi-threat detectionsystem wherein the object is a human being (or any of other animals).

FIG. 7 is yet another exemplary embodiment of the multi-threat detectionsystem for testing inanimate objects and human beings.

FIG. 8 is a perspective view of an exemplary embodiment of themulti-threat detection system including a single test unit and multipleobject units.

FIG. 9 is a cross-sectional view of an alternative embodiment of themulti-threat detection system wherein the central unit has a curvedouter surface.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the invention are described herein in the context of acheckpoint security system. However, it is to be understood that theembodiments provided herein are just exemplary embodiments, and thescope of the invention is not limited to the applications or theembodiments disclosed herein. For example, the system of the inventionmay be useful for automated testing of small parcels and mail,non-security-related testing, and nondestructive testing for any purposeincluding checking packaged consumable items (e.g., food, drugs), amongothers.

The multi-threat detection system of the invention is useful fordetecting the presence of various threatening items. A “threateningitem” is any substance and or a combination of substances and objectsthat may be of interest to a security system including but not limitedto explosives, explosive devices, improvised explosive devices, chemicalwarfare agents, industrial and other chemicals that are deemedhazardous, biological agents, contraband, drugs, weapons, andradioactive materials. The invention provides an automated system forperforming different types of tests to screen multiple threatening itemsfast, such that multiple objects can be examined in a relatively shortperiod of time. Furthermore, the system of the invention decreases thereliance on human operators, using instead a computation unit thatdetermines a risk factor based on concurrent acquisition and processingof the different test results. Thus, the system provides the much-neededmethod of increasing the accuracy of a security check test withoutcompromising the throughput.

An “ionized radiation test,” as used herein, is intended to include anyform of test that emits ionized radiation such as nuclear, X-ray, orGamma ray radiation. Examples of X ray methods include standard X-raytransmission, backscatter methods, dual or multi energy methods as wellas CT-scan. Examples of nuclear radiation source testing include methodssuch as Thermal Neutron Analysis, Pulsed fast neutron analysis,backscatter, and terahertz test, among others. A “non-ionizing test”includes methods that use a non-ionizing electromagnetic (EM) radiationsource, such as those that expose the material to a pulsed EM field andacquire the return pulse. These methods include use of high-millimeterwaves, Nuclear Magnetic Resonance (NMR) spectroscopy, Electron SpinResonance (ESR) and Nuclear Quadrapole Resonance (NQR), among others. Anadditional potential non-ionizing source includes Tetrahertz. Inaddition, “non-ionizing tests” also include methods used in detection ofconductive materials that subject an object to electromagnetic fields,either constant or pulsed wave, and detect the corresponding directionof changes in the field. “Chemical analysis” is intended to includemethods of substance detection including ion mobility spectrometry(IMS), ion trap mobility spectroscopy (ITMS), capture detection,chemiluminescence, gas chromatography/surface acoustic wave,thermo-redox, spectroscopic methods, selective polymer sensors, and MEMbased sensors, among others.

A “biological classification” classifies biological threats (e.g.,organisms, molecules) according to guidelines indicating the potentialhazard level associated with toxins, bioregulators, and epidemicallydangerous organisms (such as viruses, bacteria, and fungi). A “biometricclassification test” includes standard discrete biometric methods suchas finger prints, as well as physio-behavioral parameters indicative ofsuspect behavior.

As used herein, “simultaneously” is intended to mean a partial or acomplete temporal overlap between two or more events of the same ordifferent durations. For example, if Event A begins at time 0 and endsat time 10 and Event B begins at time 2 and ends at time 10, Event A andEvent B are occurring simultaneously. Likewise, Event C and Event D thatboth start at time 0 and end at time 7 are also occurringsimultaneously. “Sequentially,” on the other hand, indicates that thereis no temporal overlap between two or more events. If Event E begins attime 0 and ends at time 6 and Event F begins at time 7 and ends at time10, Events E and F are occurring sequentially.

A “parameter,” as used herein, is intended to include data and sets ofdata and functions, either static or dynamic.

A “threat determination function,” as used herein, is intended toinclude a function or sets of functions that define a condition thatindicates the presence of a threat. Theses function(s) can be a staticvalue, sets of static values, or a dynamic calculation. The function(s)can be either rule-based or based on other methods such as neuralnetwork.

A “risk factor” indicates the likelihood that the threatening item ispresent in the object. A “set” of risk factors may include one or morerisk factors.

FIG. 1 is a block diagram illustrating the main components of amulti-threat detection system 10 in accordance with the invention. Asshown, the multi-threat detection system 10 includes a test unit 20, acomputation unit 40, and an object unit 60 that are coupled to oneanother. The object unit 60 has a mechanism that is designed to hold anobject (e.g., a bag or a piece of luggage) that is being examined. Thetest unit 20 includes various test sources and/or equipment such as aradiation source for an X-ray exam, a chemical analysis unit for achemical exam, RF coils and or other magnetic field inductions for anon-ionizing exam. The computation unit 40, which has a processor and amemory, is configured to receive inputs from the test unit 20 and theobject unit 60 and process the inputs to generate a risk factor. Therisk factor indicates the likelihood of the object in the object unit 60containing a threatening item. Optionally, there may be a communicationunit that may include a user interface unit (not shown) that is coupledto the computation unit 40 so that the risk factor and a correspondingalert can be communicated to an operator of the multi-threat detectionsystem.

The tests that are incorporated into the test unit 20 may be anycurrently known tests for screening threatening items, and is notlimited to the examples mentioned herein. There may also be a pluralityof object units coupled to the test unit 20 and the computation unit 40so that multiple objects can be examined almost at the same time.

FIG. 2 is a block diagram of an exemplary embodiment of the multi-threatdetection system 10.

The object unit 60 has one or more doors 61 through which an object 62can be placed in the object unit 60 to be subjected to various tests. Insome embodiments, the object 62 remains stationary on a platform in theobject unit 60. In other embodiments, the object 62 is moved across theobject unit 60 through a moving mechanism 67. The moving mechanism 67may be coupled to a grasping and/or rotating mechanism 64, which may bea robotic mechanism that is capable of holding the object 62 andpositioning and rotating the object 62 in a desired location at thedesired test angle. In the embodiment shown, the moving mechanism 67 isa type of pulley system, an x-y positioner system 65, a linear motor, orany combination of these systems, and is coupled to the grasping and/orrotating mechanism 64. In an alternative embodiment, the movingmechanism may be a conveyor belt that carries the object 62 throughdifferent test stages.

The object unit 60 includes an automated receiver 69 that automaticallyprovides extra information about the owner of the object 62. In someembodiments, the extra information may include ticketing information. Inother embodiments, additional information about the owner, such as hisname, citizenship, travel destination, etc. may also be made availableby the automated receiver 69. The automated receiver 69 may beimplemented with digital/magnetic tagging, RF tagging, or other smartcard scan that identifies the owner/carrier of the object 62. Thisautomatic correlation between the object 62 and its owner/carrierfacilitates identifying the responsible person if a threatening item isfound. The object unit 60 has one or more doors 61 through which theobject can be removed. In some embodiments, the doors 61 are lockedautomatically upon the identification of a threatening item as part ofthe operational security protocols.

In this exemplary embodiment, the ionized radiation test unit 20 has anX-ray source subunit 22, a chemical analysis subunit 30, andnon-ionizing source subunit 36. The X-ray examination is done by anX-ray source 24 generating a beam and directing it toward the object 62.The X-ray source 24 is preferably supported by a rotating mechanism 26that allows the beam to be pointed in different directions, as it may bedesirable to adjust the direction of the beam according to the size andthe position of the object 62. A plurality of sensors 66 are located inthe object unit 60 and positioned to receive the X-ray beams after theypass through the object 62. Additional sensors 66 can be positioned toacquire back scatter radiation as well. The beam is received by thesensors 66 after passing through the object 62. The sensors 66 generateoutput signals based on the received beam and feed the output signals tothe computation unit 40. Where X-ray is used as one of the tests, thewalls of the X-ray subunit 22 and the object unit 60 are shielded tocontain the radiation within the object unit 60.

The chemical analysis may be performed by taking a sample from theobject 62 and running the sample through the chemical analysis subunit30. A path implemented by a flow device such as a rotational flow device32 connects the grasping and/or rotating mechanism 64 to the chemicalanalysis subunit 30 so that the sample from the object 62 can betransported to the chemical analysis subunit 30. The chemical analysismay be based on, for example, ion mobility spectroscopy, or newermethods such as selective polymers or MEMs-based sensors. Where ionmobility spectroscopy is used, the chemical analysis subunit 30 includesan ionization reaction chamber 28. An air flow is generated by a vacuumpump 33 for obtaining a gas sample from the object unit 60. The gassample travels through the adjustable closure pipes 32, which haveparticle acquisition pores 63 in proximity to the object 60 forobtaining gas samples. The rotational flow device 32 and the particleacquisition pores 63 provide a means for continuous-contact gasagitation and particle acquisition for continual analysis while theobject moves inside the object unit 60 for other tests. The particleacquisition pores 63 may be placed on the grasping and/or rotatingmechanism 64 that moves the object 62 across the object unit 60, such asthe robotic arm or the conveyor belt mentioned above. The gas sampleenters the chemical analysis subunit 30. In an exemplary embodimentusing the IMS method, the gas sample enters an ionization reactionchamber 28 through the rotational flow device 32 and becomes ionized byan ionization source. The ionized gas molecules are led to a collectorplate (not shown) located in the ionization reaction chamber 28 by anelectric field within the chamber 28. The quantity of ions arriving atthe collector plate as a function of time is measured and sent to thecomputation unit 40 in the form of one or more output signals. Amicroprocessor at the chemical analysis subunit 30 may convert thequantity of ions to a current before sending the current to thecomputation unit 40. IMS is a well-established method.

Optionally, the chemical analysis subunit 30 contains an interfacingmodule 35 to a biological detection system. If a biological detectionsystem is incorporated into the test unit 20, a biologicalclassification of the object can be obtained. A biological detectionsystem that detects molecular materials could utilize one of thechemical analysis methods. A system that is intended to identify anorganism, such as Anthrax, would utilize an automated DNA testing basedon automated polymerase chain reaction (PCR) according to the currentstate of technology.

The non-ionizing source subunit 36 may contain a radiofrequency (RF)source and/or a magnetic source, such as RF coils 38 and antennae forNQR testing and/or eddy current testing. These tests provide informationon the chemical compositions of the object and or information on theexistence of metallic and other conductive materials. Magnetic sourcesmay be a plurality of sources that vary in size and strength, so thatthe location of a threatening item can be detected as well as itspresence. Radiofrequency waves and/or a magnetic field is directed atthe object 62 and the sensors 66 receive the wave and/or the field afterit passes through the object 62. For example, where the subunit 36 is ametal detector, the metal detector may transmit low-intensity magneticfields that interrogate the object 62 as it passes through the magneticfields. A transmitter generates the magnetic field that reacts with themetal objects in its field and the sensors 66 measure the response fromthis reaction. The sensors 66 send the measurement result to thecomputation unit 40.

In addition to the X-ray exam, ion mobility spectrometry, and thenon-ionizing source test used in the embodiment of FIG. 2, any othertest may be employed by the multi-threat detection system 10 ifconsidered useful for the particular application. Also, the X-ray exam,the ion mobility spectrometry, and the non-ionizing source test may besubstituted by different tests as deemed fit by a person skilled in theart. Preferably, each of the subunits 22, 30, 36 is designed to bereplaceable independent of other subunits. Thus, substituting one testwith another will likely be a matter of replacing one subunit withanother.

The sensors 66 may be a fused-array sensor capable of collectingmultiple information either in parallel or in a multiplexed manner.Information collected may include any test results such as X-ray,terahertz ray, gamma ray, RF, chemical, nuclear radiation, and currentinformation.

The computation unit 40 includes a processor 42, a memory 44, and apower supply 46. Using a multi-variant method such as the methoddescribed below in reference to FIG. 3, the computation unit 40determines the risk factor, which indicates the likelihood that anobject will contain a threatening item. The computation unit 40 has acommunication interface 50 through which it can send visual and/or audioalerts in any mode of communication, preferably wirelessly, if an objectis likely to contain a threatening item. There is also at least one openinterface 95 that allows the computation unit 40 to communicate withanother apparatus, such as a platform for human portal system or aplatform for biometric inputs. The open interface 95 may allow wired orwireless connections to these other apparatuses.

The chemical analysis test results may be sent directly from thecollector plate in the chemical analysis subunit 30 to the computationunit 40. If desired, however, the data from the collector plate may besent to one or more sensors 66 in the object unit 60 and sent to thecomputation unit 40 indirectly from the sensors 66. When using othermethods such as passive sensors, particles can be routed directly tosensors 66. Other data, such as X-ray data, are collected by the sensors66 and sent to the computation unit 40. As used herein, “sensors”include any type of device that is capable of making a physical orelectrical measurement and generating an output signal for thecomputation unit 40, such as sensors 66 in the object unit 20 and thecollector plate in the chemical analysis subunit 30.

Although FIG. 2 shows the test unit 20, the computation unit 40, and theobject unit 60 as three separate components, the division is conceptualand the physical units do not necessarily have to correlate with theconceptual division. For example, all three units may be contained inone housing, or the test unit 20 and the object unit 60 may be containedin the same housing while the computation unit 40 is in a remotelocation.

FIG. 3 is a block diagram illustrating the modules of the computationunit 40 for executing a threatening item identification method. Asdescribed above, the computation unit 40 receives inputs from the testunit 20 and/or the object unit 60. These inputs originate as raw datacollected by the sensors 66 and/or the collector plate in ion mobilityspectrometry (or another chemical sensor). As shown in the diagram, themethod of the invention uses a set of functional modules 116, 118, 120,122, 124, 126, 128, 206, 208 to process the various inputs from thesensors 66 and the sensor in the test unit 20 (e.g., the collectorplate). Using these modules, values are calculated for variousparameters such as texture, density, electrical conductivity, molecularclassification, location classification, radiation classification,visual classification, biological classification, and biometricclassification for the object 62. Where the object 62 is something likea bag that contains multiple components, the components may beautomatically divided according to texture, density, conductivity, etc.so that each component is classified separately.

In the particular embodiment of the threatening item identificationmethod that is shown in FIG. 3, the active radiation (e.g., X-ray)detection results are used for determination of texture classification,density classification, shape context classification, locationclassification, and visual classification. The radioactive level of theobject may be determined for radiation classification. Current data orinduced EM field responses are used for parameters such as textureclassification, conductivity classification, and locationclassification. The magnetic response is used for calculating parameterssuch as molecular classification, density classification, and locationclassification. Any chemical analysis result is used for molecularclassification. Output signals from the sensors 66 and output signalsfrom the chemical analysis subunit 30 are fed to the different modulesin parallel, so that the values for all the parameters of theclassification areas such as texture, density, etc. can be determinedsubstantially simultaneously.

After the parameters based on values and functions for each of theseclassification areas is determined, the values are collectivelyprocessed in a multi-variant data matrix module 300 to generate a riskfactor. The multi-variant data matrix 300 arranges the plurality ofclassification parameters from function matrices 116, 118, 120, 122,124, 126, 128, 206, 208, 210 into an n-dimensional data matrix. Forinstance, visual classification function matrix 124 would yield numerousvisualization data [V] as a function of number of (1 . . . n) andmeasurement and angles (Φ) depending on the number of rotationsperformed by the grasping and/or rotating mechanism 64, so one form ofdata would be V=f(Φ)n. Additionally, a series of visualization data [V]related to density parameters [D] at each angle Φ would yield the set ofparameters V=f(D, Φ, n). Another set of parameters fed into themulti-variant data matrix 300 would be conductivity classifications fromthe conductivity classification functions matrix 120 and would similarlyyield an array of interrelated parameters, for example conductivity [Z]as having varying intensities (i) as a function of location (l) yieldingone set of Z=f(i,l). These three exemplary functions V=f(Φ, n), V=f(D,Φ, n), and Z=f(i,l) would be arranged in the multi variant data matrix300 in such a way that provides multiple attributes for particularthree-dimensional locations, as well as global attributes, throughoutthe screened object. More generally, all classification function matrixblocks will produce numerous parameter sets, so that an n-dimensionalparameter matrix is produced for processing in block 310.

The n-dimensional parameter matrix generated in block 310 enablesnumerous calculations and processing of dependent and interdependentparameters to be performed in block 310. The parameters from themulti-variant data matrix module 300 is submitted to the threatdetermination functions, which include running sets of hybridcalculations. Hybrid calculations include combinations of rule-based andother methods (such as neural network or other artificial intelligence(AI)-based algorithms) and comparison of the result against real-worldknowledge criteria and conditions (block 310). In some embodiments, anexample of a rule-based decision would combine testing some or all ofthe parameter(s) against thresholds. For example, a condition such as“If texture classification T(Φ, L)n>3, density classification D(Φ,L)n>4, conductivity classification Z(i,l)n>4, locationclassification >3, and radiation classification >1” could be used as acondition for determining one type of risk factor and possiblygenerating an alert. Calculations may be any simple or complexcombination of the individual parameter values calculated by test block310 to determine sets of risk factors. Sets of risk factors representvarious categories of threats that are likely to be present in theobject. For instance, there may be a category of threat functionsassociated with the likelihood of a biological event which would producea risk factor for this category, there may also be a category of threatfunctions associated with the likelihood of an explosive threat whichwould produce a risk factor for the explosive category, and yet theremay be a category threat functions associated with a general likelihoodevoked by a combination of attributes not necessarily specifically tothe material type. Different calculations may yield a number of riskfactors within each category. The threat functions include testconditions and apply criteria based on pre-existing real world knowledgeon signals and combinations of signals identifying threats.

If a high-enough risk factor is determined that the preset set of threatthresholds are satisfied, depending on the embodiment, the location,quantity, and type of the threatening item may be estimated (block 320),an alert may also be generated (block 330). Whether a risk factor ishigh enough to trigger the alert depends on the sensitivity settingswithin the system, which has a default setting and is reconfigurable bythe user. An “alert” may include a visual or audio signal for notifyingthe operator that a threatening item may have been identified, and mayalso include taking other operational actions such as closure/locking ofthe door 61 in the object unit 60. Optionally, a signal (e.g., a greenlight) may be generated to indicate that an object is clear ofthreatening items (block 325).

FIG. 4 is a cross-sectional view of an exemplary embodiment of themulti-threat detection system 10 including a single test unit 20 andmultiple object units 60 a-60 e. FIG. 8 is a perspective view of thesystem 10. In this embodiment, the centrally located test unit 20 hasflat outer surfaces that interface the object units 60 a-60 e. As shown,the test unit 20 is located centrally with respect to the object units60 so that an object can be tested by the test unit 20 regardless ofwhich object unit it is in. The test unit 20 and the object unit 60 maybe made of any material with structural integrity including variousmetals (e.g., steel) or composite material. Preferably, there is arotating mechanism in the test unit 20 that allows the direction of thetest beam, etc. to be adjusted depending on which object is beingtested. Once all the object units are filled, the test unit performstests on the objects by turning incrementally between each object unit60 as shown by the arrows. Some tests are performed sequentially. Forexample, if an X-ray test is performed, the X-ray beam is directed fromthe test unit 20 to the multiple object units 60 a-60 e sequentially,e.g. in a predetermined order. However, other tests are performedsimultaneously for the multiple object units 60 a-60 e. For example, ifa chemical analysis test is performed, a sample of each object in themultiple object units 60 a-60 e can be taken simultaneously, as eachobject unit has its own rotation flow device 32, grasping and/orrotating mechanism 64, and particle acquisition pores 63. Thus,depending on the tests that are included in the particular embodiment,the overall testing may be partly sequential and partly simultaneous forthe multiple object units 60 a-60 e. All the test data are sent to thecomputation unit 40, preferably as soon as they are obtained.

The output signals from the sensors 66 (and the collector plate of thechemical analysis subunit 30, if applicable) may be processed by asingle computation unit 40 or a plurality of computation units 40. Wherea single computation unit 40 is used, the computation unit 40 keeps theobjects separate so that it yields five different results, one for eachobject 62.

The embodiment of FIG. 4 allows multiple objects to be processed quicklycompared to the current security check system where passengers form asingle line and one object (e.g., bag) is processed at a time.Therefore, all the tests incorporated into the test unit 20 can beperformed for each of the objects in the object units 60 a-60 e withoutcompromising the traffic flow.

The multi-threat detection system 10 of FIG. 4 may be designed as amodular unit, so that the number of object units 60 is adjustable. Thus,if a first area is getting heavy traffic while traffic in a second areahas slowed down, a few of the object units from the second area can beused for the first area by simply being detached from one test unit 20and being attached to another test unit 20. The detaching-and-attachingmechanism may use hook systems and/or a clasping/grasping/latchingmechanism. This flexibility results in additional cost savings forpublic entities that would use the multi-threat detection system 10. Theobject units 60 a-60 e are substantially identical to one other.

Additionally, the platform on which the object 62 is placed in theobject unit 60 may have a sensor, such as a weight or optical sensor,that signals to the test unit 20 whether the particular object unit 60is in use or not. So, if only object units 60 a, 60 b, 60 d, and 60 eare used for some reason, the test unit 20 will not waste time sendingtest beams and collecting samples from the empty object unit 60 c andthe system 10 will automatically optimize its testing protocols. Thesystem 10 may include a processor for making this type of determination.A sensor is placed either in each object unit 60 or in the test unit 20to detect an output signal indicating that an object in the object unit60 has been tested.

Although the particular embodiment shows the units as having hexagonalshapes for a honeycomb configuration, this is just an example and not alimitation of the invention. For example, the test unit 20 may have anypolygonal or curved cross section other than a hexagon. FIG. 9, forexample, shows a cross-sectional view of a multi-threat detection system10 wherein the test unit 20 has a curved outer surface (as opposed toflat outer surfaces as in the embodiment of FIG. 4). The shapes of theobject units 60 a-60 e are adapted so they can efficiently and securelylatch onto the test unit 20. Furthermore, the structure allows aresource in a central unit (e.g., the test unit 20) to be shared amongthe surrounding compartments (e.g., object units 60) in a fast andspace-efficient manner, making the structure useful for variousapplications other than detection of threatening objects. For example,where multiple objects need to be encoded with a piece of data, the datasource can be placed in the central unit so that objects in thesurrounding compartments can read the data. In a case of laser etching,objects in the compartments could receive data encoding from the centralunit.

FIG. 5 is a block diagram showing the test unit 20 and the object units60 a-60 e. In the particular embodiment, a single computation unit 40 isused for all the object units 60 a-60 e. Each of the object units 60a-60 e contains a moving device, such as a mechanical mechanism, multiaxis manipulator, robotic mechanism, a conveyor belt, or any otherrotating and linear mechanism and a sensor array, as described above inreference to FIG. 2. The moving device allows both linear and rotationalmovement. The test unit 20 has four subunits: an ionized radiationsource subunit, a chemical analysis subunit, a non-ionizing radiationsource subunit, and a magnetic field induction subunit. Each of theobject units 60 a-60 e is coupled to the test unit 20 and thecomputation unit 40.

FIG. 6 is another exemplary embodiment of the multi-threat detectionsystem 10 wherein the object is a human being (or any of other animals).In the particular embodiment that is shown, the test unit 20 has twoobject units 60 a, 60 b attached to it. Naturally, tests involvingradiation will be used with caution, by choosing appropriate radiationsources and parameters when the “objects” being tested are human beings.If desired, a camera may be installed somewhere in the test unit 20 orthe object unit 60 a and/or 60 b to obtain images of objects in order toobtain a biometric classification and/or transmit images to an operator.

FIG. 7 is yet another exemplary embodiment of the multi-threat detectionsystem 10 for testing inanimate objects and human beings. The particularembodiment has the test unit 20 with five object units 60 a-60 e fortesting inanimate objects and a portal 60 f for human beings or animalsto pass through. The test unit 20 tests objects in the object units 60a-60 e and human beings in the object unit 60 f that are in each of theobject units 60 a-60 f. However, all the object units and both testunits would still feed signals to a single computation unit 40.

The invention allows detection of threatening items with increasedaccuracy compared to the currently available system. While the currentlyavailable systems use a sequence of separate equipment, each equipmentusing only one test and generating a test result based only on that onetest, the system of the invention relies on a combination of a pluralityof parameters. Thus, while a bomb that has a low level of explosive anda small amount of conductive material may escape detection by thecurrent system because both materials are present in amounts below thethreshold levels, the object could be caught by the system of theinvention because the presence of a certain combination of indicativematerials and vicinity parameters included in the threat determinationfunctions could trigger an alarm. The use of combinations of parametersallows greater flexibility and increased accuracy in detecting thepresence of threatening items.

The invention also allows detection of a general threatening item,material deformation, and fractures in the case of a nondestructivetesting. This is different from the current system that targets specificitems/materials such as explosives, drugs, weapons, etc. By detectingthe presence of a general combination of potentially hazardousmaterials, the system of the invention makes it more difficult forcreative new dangerous devices to pass through the security system.

While the foregoing has been with reference to particular embodiments ofthe invention, it will be appreciated by those skilled in the art thatchanges in this embodiment may be made without departing from theprinciples and spirit of the invention.

1. A system for screening an object for a threatening item, the system comprising: a test unit configured to subject the object to a combination of two or more different types of tests; sensors configured to receive test outcome from the object and generate corresponding output signals; a computation unit receiving the output signals and processing the output signals to generate parameter values, the computation unit combining the parameter values from the different types of tests to determine a set of risk factors indicating a likelihood that the threatening item is present in the object, wherein the parameter values include visualization data obtained from different measurement angles.
 2. The system of claim 1, wherein the two or more tests are performed simultaneously.
 3. The system of claim 1, wherein the two or more tests are performed sequentially.
 4. The system of claim 1, wherein the computation unit processes the output signals from different sensors simultaneously.
 5. The system of claim 1, wherein the tests are selected from ionizing radiation test, chemical analysis, and non-ionizing test.
 6. The system of claim 1, wherein the sensors are in the form of a fused sensor array.
 7. The system of claim 1, wherein the computation unit determines a set of parameters that include one or more of texture, density, electrical conductivity, molecular class, location, visual classification, radioactive potential, biological class, and biometric class of the object based on the output signals from the sensors.
 8. The system of claim 7, wherein an output signal from one of the sensors is used to determine values for multiple parameters.
 9. The system of claim 1, wherein the computation unit has a threat determination fraction that includes conditions that determine the set of risk factors, the system further comprising an interface unit for generating an alert if one or more risk factors of the set of risk factors is determined.
 10. The system of claim 1 further comprising a moving mechanism in the object unit for moving the object to a desired location in the object unit.
 11. The system of claim 1 further comprising a rotating mechanism configured to hold the object and rotate it to adjust the object's angle for testing.
 12. The system of claim 1 further comprising a first object unit designed to hold the object, which is a first object, and a second object unit designed to hold a second object, wherein the test unit tests the first object and the second object.
 13. The system of claim 12, wherein the second object unit is a modular unit that is detachable from the test unit.
 14. The system of claim 12, wherein the test unit has a mechanism that allows the test unit to test the first object and the second object sequentially.
 15. The system of claim 12, wherein the test unit tests the first object and the second object simultaneously.
 16. The system of claim 1, wherein the test unit comprises subunits, each of the subunits containing a unique test equipment and being independently replaceable with a different subunit.
 17. The system of claim 1 further comprising a camera configured to obtain an image of the object.
 18. The system of claim 1 further comprising an automated receiver that identifies an owner of the object and provides information about the owner.
 19. The system of claim 1, wherein the object is in an object unit that has a physically separate compartment from the test unit.
 20. The system of claim 1, wherein the object is a first object and is placed in a first object unit that is designed to hold the first object, further comprising a second object unit designed to hold a second object, wherein the test unit subjects each of the first object unit and the second object unit to the combination of two or more tests and the computation unit receives output signals from the first object unit and the second object unit to calculate risk factors for the first and second objects.
 21. A method of screening an object for a threatening item, the method comprising: subjecting the object to a combination of different types of tests for identifying properties of the object; reading output signals from sensors positioned to receive test outcome from the object; processing the output signals individually to generate parameter values; and combining the parameter values from the different types of tests and using visualization data obtained from different measurement angles to determine a risk factor that indicates a likelihood that the threatening item is present in the object.
 22. The method of claim 21 further comprising subjecting the object to the combination of tests simultaneously.
 23. The method of claim 21 further comprising subjecting the object to the combination of tests sequentially.
 24. The method of claim 21, wherein processing different output signals comprises processing the output signals simultaneously.
 25. The method of claim 21 further comprising selecting the combination of tests from ionizing radiation test, chemical analysis, and non-ionizing test.
 26. The method of claim 21 further comprising determining values for a set of parameters based on the output signals, wherein the set of parameters includes one or more of texture, density, electrical conductivity, visual classification, molecular class, location, radioactive potential, biological class, and biometric class.
 27. The method of claim 26 further comprising determining values for multiple parameters by using one output signal of the output signals.
 28. The method of claim 26 further comprising determining the risk factor by combining values for the set of parameters according to pre-existing threat determination function.
 29. The method of claim 21 further comprising generating an alert based on the risk factor.
 30. The method of claim 21 further comprising moving the object to properly position the object for different tests.
 31. The method of claim 21, wherein the object is a first object, further comprising a first object unit designed to hold the first object and a second object unit designed to hold a second object, further comprising testing a second object testing the first object.
 32. The method of claim 21, wherein the object is a first object in a first object unit that is designed to hold the first object, further comprising testing a second object in a second object unit while the first object is being tested.
 33. The method of claim 21 further comprising obtaining an image of the object.
 34. The method of claim 21, wherein the object is a first object in a first object unit, further comprising: identifying a second object in a second object unit and subjecting the second object to the combination of tests; and determining risk factors for the first object and the second object separately. 